swept sine with ramping amplitude on NI 5411

[Travis_W]

Although you can load in a User-Defined Standard Function, your swept amplitude sine application is not the intended use for this functionality, and there will be resulting limitations. 

This waveform has to be exactly 16384 samples long, which might not be a problem on its own, but the User-Defined Standard Function expects that these 16384 samples make up 1 period of the waveform you want to generate.  The way that different output frequencies are accomplished is through decimation of this waveform.  For your application, this may lead to problems with your perceived output frequency.  What sine frequency sine wave were you looking to generate?

One of the newer Arbitrary Waveform Generators would fit your application better.

Have a great day!
Travis White

[kmh]

I wanted to generate a ramped amplitude sine waveform(y(t)=Atsin(wt) where A is the maximum amplitude,t varies from say 0-1 sec,and w is a fixed frequency)  using a PXI 5401.Because of glitches in the output when the 5401 switched amplitudes,It was suggested that I go in for one of the newer arbitrary signal generators.Which one would be the best for my application?I would need to use the arbitrary signal generator with a PXI 5122 digitizer.

The generator should be able to trigger the digitizer so that the digitizer starts measuring as soon as the generator starts generating

kmh

[kirsch]

The NI 5402 or 5406 function generators (not arbitrary signal generator) should be sufficient if you are ok using software timed amplitude changes (which appears to be the case given that you tried this on a 5401). You can use Standard Function Mode to output the sine wave and then change the amplitude from your program using the Digital Gain property, which provides glitch-less amplitude control at the expense of dynamic range (bits).

If you want the amplitude to be HW timed, then you'll need to use one of our Arbitrary Waveform Generators, such as the NI 5412 and set up your generation using Arbitrary Waveform Mode, Sequence Mode or Script Mode.

Exporting the Started Event to trigger the digitizer will not be a problem on any of these products.

Marcos

[juggy]

Hi

I am very interested  in knowing how to set the digital gain property for the NI 5421. Can you please elaborate? I want to use it for an arbitrary waveform that is stored in a user generated file. If you can please point me to the right C function that sets the attribute "NIFGEN_ATTR_DIGITAL_GAIN", it will be most helpful.

Thanks
Jagadish

[garretth]

Hello Jagadish,

You can set any of the FGEN attributes using the Set Attributes functions. You can set this particular attribute with the niFgen_SetAttributeViReal64 function. The prototype looks like this:

ViStatus niFgen_SetAttributeViReal64 (ViSession vi, ViConstString channelName, ViAttr attributeID, ViReal64 attributeValue);

There is more detailed information available in the NI Signal Generators Help file.

Hope this helps!

[curryfishead]

Hi,

I need to generare 3 sine signal with amplitude ramping up every time i press the button
and Amplitude Ramping down when the button release.

will this possible to achieve with board PCI 6723?

Can any one help?
Any example?

Many Thanks!

[garretth]

Hey Curryfish,

You definetely can do this... repost your question in the DAQ section of the forums and I'll be happy to give you some ideas. This forum is for signal generators which have a different architecture and programming API from your 6723 DAQ card... so it makes sense to keep them separate.

Thanks!